Students will know what 3D printing is, the history of it, how it can be used, and how to create 3D models. This course will teach students how to prepare for the future world of 3D printers.
3D printing processes vary from printer to printer. Each company or manufacturer uses the method that first its needs best. The end result is always the same which is the additive process of adding layers to form the desired object for printing.
There are 7 categories of printing processes according to the American Society for Testing and Materials. We’ve already discussed some of them in class. These categories are:
1. Vat Photopolymerisation which is subdivided into Digital Light Processing (DLP), Stereolithography (SLA), and Continuous Liquid Interface Production (CLIP)
2. Material Jetting
3. Binder Jetting
4. Sheet Lamination
5. Material Extrusion which is subdivided into Fused Deposition Modeling (FDM) and Fused Filament Fabrication (FFF)
6. Power Bed Fusion
7. Directed Energy Deposition
The most commonly used method in Material Extrusion is Fused Deposition Modeling (FDM). FDM uses a plastic filament or a metal wire which is connected to a nozzle to turn flow on and off. The nozzle in turns melts the material and moves both horizontally and vertically. This is done via computer aided software.
As the nozzle releases the material into layers taking the shape of the required object the material hardens straightaway. The plastic filament types most used are polyactic acid and acrylonitrile butadiene styrene. Of course the process isn’t just limited to these as even wood fill can be used as material but these are the most commonly used ones.
Scott Crump patented FDM in the 80s then went on to start a company called Stratasys in 1988. FFF on the other hand was coined by RepRap. It is the exact same thing as FDM but the term FFF can be used freely without any legal constraints.
The next technique is Power Bed Fusion. The dominant technology in Power Bed Fusion is Selective Laser Sintering (SLS). Through a laser, SLS fuses small particles of any material such as glass, plastic, or metal into a 3D dimensional object. The layer does this by scanning the cross sections generated on the surface of a powder bed. The powder bed is lowered by one layer after each scan. New layers of material are added sub sequentially in the same pattern.
Directed Energy Deposition is used in rapid manufacturing and in the metal industry. Simply, a nozzle releases the powder (metal or wire) and a laser melts it to form the 3D object. Sciaky is a leading company when it comes to Directed Energy Deposition.
These are all the 3D printing technologies in brief. There’s much more to it of course but this covers it for anyone new to 3D printing.